CN1042321C - Method and equipment for preparing ceramics grade powder of uranium dioxide - Google Patents
Method and equipment for preparing ceramics grade powder of uranium dioxide Download PDFInfo
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- CN1042321C CN1042321C CN96103239A CN96103239A CN1042321C CN 1042321 C CN1042321 C CN 1042321C CN 96103239 A CN96103239 A CN 96103239A CN 96103239 A CN96103239 A CN 96103239A CN 1042321 C CN1042321 C CN 1042321C
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- uranium dioxide
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Abstract
The present invention has a great improvement on the basis of the existing method and the existing equipment for preparing the powder of uranium dioxide, wherein the conditions of the reaction for the decomposition and the reduction of AUC material, such as temperature and fluidizing velocity, are scientifically selected and adjusted, and a feeding system, a fluidized bed, a stabilizing bed and an exhaust gas treating device of the existing equipment are improved greatly. Therefore, raw materials and energy resource are considerably saved, the equipment is convenient in use and is easy to maintain.
Description
The invention belongs to the preparation method field of metallic compound, be specifically related to prepare ceramic grade UO
2The method and apparatus of powder.
Preparation ceramic grade UO
2The method of powder is a lot, and what traditional employing was more is to convert UO by ADU to pushing away boat stove or rotary kiln
2, China nuclear fuel factory still converts UO with rotary kiln to by ADU so far
2, the UO of production
2The powder quality lack of homogeneity, processability and sintering character instability, the pellet yield rate is low to making.New method is constantly sought by many in the world countries, and Germany nuclear chemistry Usiminas (NUKem) and reactor fuel element affiliated company (RBU) joint study go out the AUC flow process, put into production with technical scale in 1969.AUC (Ammonium UranglCarbonate) is the abbreviation of aut.Disclosing the AUC flow process in " ceramic uranium dioxide preparation " book that the China Atomic Energy Press published in 1987 uses fluidized-bed by H exactly
2Gas is made fluidizing medium and reductive agent decomposition-reduction AUC, and adapted stabilization fluidized-bed is with firm reductive UO
2Powder carries out stabilization treatment, obtains more required UO
2Oxygen/uranium metal atomic ratio and other satisfy the performance index of processing requirement.
The equipment (Fig. 2) of prior art fluidised bed decomposition reduction AUC partly is made up of four of feeding device, decomposition-reduction fluidized-bed, stabilization bed and exhaust treatment systems etc.Principle of work: feed nitrogen to fluidized-bed earlier, the back feeds hydrogen, starts to add electrothermal stove.AUC is joined in the loading hopper, blowback strainer tube periodically, stirring the AUC powder with agitator flows downward, use nitrogen pressurising sebific duct ball valve again,, stop powder to fall to also stoping on the waste gas in the bed and scurry owing to the rubber hose pressurized is closed, then following sebific duct ball valve is put pressure, sebific duct recovers the garden column, and powder falls to just joining in the fluidized-bed, and charges into nitrogen to the sebific duct ball valve sebific duct pressurized is closed; The sebific duct ball valve is put pressure again and made sebific duct recover the garden column, powder falls, and alternating movement adds the AUC powder in the fluidized-bed like this, has also fed nitrogen in filling tube in addition, prevents to scurry on the interior waste gas.After the AUC material joins in the fluidized-bed, under 500-550 ℃ temperature, carry out decomposition reaction, after under 600 ℃ temperature, carry out the fluidisation reduction reaction again, use the hydrogen fluidisation, fluidizing velocity is 0.32 meter per second.The sintered-metal filter of waste gas behind the decomposition-reduction on the fluidized bed top filters, first cyclonic separator dedusting outside bed again, and second cyclonic separator dedusting, sack cleaner dedusting, and a water scrubber drip washing enter ventilation system at last.Reduction reaction is opened turning valve with UO after finishing
2Powder is discharged in the stabilization bed, by the water cooling of chuck, introduces the UO that aeriferous nitrogen stabilization just made ceramic grade in 20 minutes when being chilled to 40 ℃
2Powder, finished product UO
2Powder is delivered in the mixing machine by suction.The regularly blowback of production process middle filtrator.The UO of production ceramic grade in this way
2Powder, highly efficient in productivity, the powder quality uniformity is easy to realize serialization, the automatization of producing also be easy to the protection of radioactive substance.But exist some not enough as: a. fluidizing velocity height (0.32 meter per second) causes hydrogen gas consumption too big; B. the fluidized-bed structure complexity is keeped in repair frequency height, and feed mechanism complexity and often replacing component especially expect that as alternately rousing with two rubber diaphragm valves the rubber diaphragm life-span has only two months in bed.C. utility appliance is many, as vent gas treatment at the bed peripheral hardware twice cyclonic separators, a sack cleaner and a washer.D. the selection of decomposition-reduction temperature is suitable inadequately.Decomposition temperature is 500-550 ℃, and reduction temperature is 600 ℃.
The purpose of this invention is to provide a kind of hydrogen consumption of saving greatly, processing condition are more reasonable, and simplified equipment is easy to use, the novel method and the equipment of the preparation ceramic grade UO2 powder of good product quality.
Technical scheme of the present invention is as follows:
1. determine that the AUC decomposition temperature is 360-400 ℃, reduction temperature is 650-700 ℃.Reduction soaking time 40-60 branch.Best reduction temperature is 700 ℃, and best reduction soaking time is 50 minutes, and best decomposition temperature is 400 ℃.
According at H
2Pyrolysis behavior and the reduction reaction rule of AUC in the fluidized-bed of development voluntarily under the atmosphere, the decomposition temperature of correctly having determined AUC is 360-400 ℃; Reduction temperature is 650-700 ℃.These two temperature are according to repeatedly testing and the processing performance requirement of powder is determined, help keeping original characteristic of AUC crystal and UO under such temperature condition
2Powder is inherited AUC particles of powder pattern and is guaranteed UO
2The processing performance of powder.
2. determine that fluidizing velocity is the 0.01-0.05 meter per second.Through experimental results demonstrate that fluidizing velocity is that 0.02 meter per second is the most suitable.3. improved feed system.It is by dc speed-regulating motor, and flat hopper, feed-pipe and feeding screw are formed.
The elongate tubular feeding unit is adopted in charging, and it is by elongate tubular feed-pipe, flat hopper, and feeding screw is formed, and the side of elongate tubular feed-pipe is adorned a feeding screw, flat hopper be contained in the feeding screw screw shaft above, and become one with the feeding screw shell.Such structure makes an interior waste gas because of mobile N
2Gas and keeping apart fully with the material in the hopper, bed body metallic conductance the heat still radiant heat in the bed all can not pass in the hopper, so the AUC material in the hopper is exsiccant all the time.Turn round off and on by the motor on the computer controlled automatic screw shaft, the AUC material aly is successfully added in the fluidized-bed.
4. simplification tail gas treatment device.
Waste gas only filters through the sintered filter of bed inner top, by vapor pipe, just can enter ventilation system after the water washing of washer again outside bed.Compare with the equipment of Germany and to have reduced 3-stage dust-removal.
5. fluidized-bed and stabilization bed bed structure are improved.Fluidized-bed of the present invention and stabilization bed have increased expanding reach, and the sintrered nickel gas distribution grid is arranged at stabilization bed bottom.
Advantage of the present invention:
1. processing condition are more reasonable.It is comparatively suitable when fluidizing velocity is 0.02 meter per second.Under this fluidizing velocity, in the bed material particles just suspended and even dispersion at H
2Among the gas, and move up and down.Waste gas after the decomposition is taken away by intergranular air-flow rapidly, fresh reductive agent (H
2) enter granule interior easily, chemical reaction evenly and is promptly carried out.Because of fluidizing velocity is low, the heat that gas is taken away in the bed is also few, and not only furnace temperature is easy to control and constant, and has saved the heating power of electric furnace.Because of fluidizing velocity is little, be unlikely and mixed strong and particle collides fierceness mutually because of material, it is broken to cause particle to break, and the material fine powder increases, and causes the powder compacting performance depreciation.Because of fluidizing velocity is low, reduced the consumption of hydrogen greatly, under the identical situation of output equal mass, this fluidized-bed is 1/14 of a German fluidized-bed hydrogen consumption, has saved starting material greatly.
The decomposition temperature of the AUC that the present invention adopts is 360-400 ℃, and the decomposition temperature of prior art AUC is 500-550 ℃.Decomposition temperature is low, decomposes acutely not help UO
2Powder is inherited the granule-morphology of AUC, guarantees that powder has good processability.The decomposition temperature height decomposes acutely, and the AUC particle is easily cracked, causes the powder fragmentation, and processability degenerates.Reduction temperature of the present invention is 700 ℃, and the reduction temperature of prior art is 600 ℃, according to experimental results show that 700 ℃ of whens reduction, UO
2The loose density of powder and flowability are best.
Two kinds of UO that technology is made
2The contrast of powder physicals:
| The loose density gram per centimeter | Specific surface area rice/gram | Mobile Grams Per Second | |
| Prior art | 0.91 | 5.79 | 2.13 |
| The present invention | 1.81 | 9.3 | 2.56 |
2. this feed system is simple, durable, reliable, need not often change component.It has successfully solved the reinforced difficult problem of this problem, and the durable component of reliably need not often changing of mechanism keep in repair with frequent.Reinforced difficult major cause is: the AUC powder is very light, and adding has the waste gas of certain pressure HN in the fluidized-bed
3, CO
2And H
2O vapour will spray everywhere scurries, if charging process is unreasonable, not only powder is difficult to add on the contrary and regurgitates, or HN
3, CO
2And H
2O vapour enters hopper smoked the wetting of AUC is lumpd and occluding mechanism.Also have a requirement must add off and on exactly to reinforced aly, add a after a AUC of to be added that decomposes fully again.In process of production charging mechanism start or stop all can not to allow the bed in waste gas enter charging mechanism and hopper.The present invention preferably resolves the problems referred to above, and simple in structure, durable, operation control is also convenient.
Vent gas treatment simple, reduced number of devices, reduced manufacturing expense.Alleviated maintenance management workload to radioactivity equipment.Tail gas of the present invention only outside bed a water washing get final product, compared with prior art, reduced two cyclonic separators and a sack cleaner.
4. the sintrered nickel gas distribution grid has been adorned in the bottom of stabilization bed of the present invention.Stabilization bed bottom has the sintrered nickel gas distribution grid not only to make nitrogen and two kinds of gases of air mix but also make UO
2Powder is adsorb oxygen very equably, makes the powder quality uniformity.
5. fluidized-bed and stabilization bed increase expanding reach can make the transfer lime chap, makes gas velocity slack-off, and micro mist is difficult for going out with waste gas, and good filtration effect has been saved the complex apparatus of recycling.
The present invention has following accompanying drawing:
Fig. 1 is a front view of the present invention
Fig. 2 is that the flat hopper 23-of prior art front view 1-dc speed-regulating motor 21-nitrogen inlet 2-feeding screw 22-hydrogen inlet 3-nitrogen inlet 4-feed pipe 24-AUC entrance 5-sintrered nickel filter 25-pressure reduction is taken over 6-fluid bed expanding reach 26-pressure tap 7-decomposition-reduction fluid bed 27-pressure reduction adapter 8-electric furnace 28-pressure tap 9-multi-point temperature measurement pipe 29-pressure reduction adapter 10-sintrered nickel gas distribution grid 30-pressure tap 11-cone valve 31-pressure reduction adapter 12-sintrered nickel screen pipe 32-pressure tap 13-stabilisation bed expanding reach 33-tail gas outlet 14-stabilisation bed 34-tail gas outlet 15-sintrered nickel gas distribution grid 35-UO2Powder 16-finished container 36-washer 17-nitrogen inlet 37-washer 18-air advances 38-water jacket 19-water coolant and advances 39-vapor pipe 20-cooling water outlet 40-vapor pipe
Embodiment:
Start blower fan, with the negative pressure transportation method AUC material is delivered in the flat hopper 3, start other control panel then, through feed system the AUC material is added in the fluidized-bed 7, charge into nitrogen earlier in fluidized-bed 7, flow is 1000 liters/hour, charge into hydrogen, fluidizing velocity is 0.02 meter per second, after reaction finishes, with UO
2Powder is discharged in the stabilization bed 14, pours hydrogen, and flow is 800 liters/hour, carries out stabilization treatment 30 minutes, is discharged in the finished container 16 the same prior art of other step then.
Preparation ceramic grade UO
2The equipment of powder, feeding unit is made up of elongate tubular feed-pipe 4, flat hopper 3, feeding screw 2, elongate tubular feed-pipe 4 sides are adorned a feeding screw 2, flat hopper 3 be contained in screw feed en-trance 2 screw shaft above, and become one with feeding screw 2 shells.Fluidized-bed 7 has increased expanding reach 6 and 13 with 14 bodies of stabilization bed, and stabilization bed 14 bottoms are equipped with sintering metal nickel gas distribution grid 15, and tail gas treatment device is a sintrered nickel strainer 12, is connected with washer 36,37 by vapor pipe 39,40.The same known technology of miscellaneous equipment.
Claims (4)
1. method for preparing ceramics grade powder of uranium dioxide, comprise the decomposition reaction of using hydrogen to make fluidizing medium, reduction reaction, stabilization treatment, it is characterized in that: the AUC decomposition temperature is 360-400 ℃, reduction temperature is 650-700 ℃, and fluidizing velocity is the 0.01-0.05 meter per second, and the reduction soaking time is 40-60 minute.
2. the method for preparing ceramics grade powder of uranium dioxide according to claim 1 is characterized in that: AUC is best, and decomposition temperature is 400 ℃, and best reduction temperature is 700 ℃, and best fluidizing velocity is 0.02 meter per second, and best reduction soaking time is 50 minutes.
3. equipment for preparing ceramics grade powder of uranium dioxide, comprise motor (1), electric furnace (8), finished container (16), hydrogen inlet (22), tail gas outlet (33), washer (36), (37) is characterized in that: the elongate tubular feeding unit is adopted in charging, fluidized-bed (7) has increased expanding reach (6) with stabilization bed (14) bed body, (13), stabilization bed (14) bottom is equipped with sintering metal nickel gas distribution grid (15), and tail gas treatment device is that sintrered nickel strainer (12) is by vapor pipe (39), (40) with washer (36), (37) link to each other.
4. the equipment of preparation ceramics grade powder of uranium dioxide according to claim 3, it is characterized in that: feeding unit is by elongate tubular feed-pipe (4), flat hopper (3), feeding screw (2) is formed, the side of elongate tubular feed-pipe (4) is adorned a feeding screw (2), flat hopper (3) is contained in above the screw shaft of feeding screw (2), and becomes one with feeding screw (2) shell.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN96103239A CN1042321C (en) | 1996-03-12 | 1996-03-12 | Method and equipment for preparing ceramics grade powder of uranium dioxide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN96103239A CN1042321C (en) | 1996-03-12 | 1996-03-12 | Method and equipment for preparing ceramics grade powder of uranium dioxide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1134918A CN1134918A (en) | 1996-11-06 |
| CN1042321C true CN1042321C (en) | 1999-03-03 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN96103239A Expired - Lifetime CN1042321C (en) | 1996-03-12 | 1996-03-12 | Method and equipment for preparing ceramics grade powder of uranium dioxide |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105668640B (en) * | 2016-02-01 | 2017-12-29 | 北京大学 | One kind prepares ceramic grade UO2The method of nuclear fuel |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3963828A (en) * | 1973-09-06 | 1976-06-15 | Siemens Aktiengesellschaft | Manufacture of uranium dioxide powder |
| EP0031066A1 (en) * | 1979-12-20 | 1981-07-01 | Alkem Gmbh | Process for producing nuclear-fuel oxides |
| CN86104023A (en) * | 1985-06-11 | 1987-04-22 | 三菱金属株式会社 | The method of convert from uranic fluoride to uranium dioxide |
-
1996
- 1996-03-12 CN CN96103239A patent/CN1042321C/en not_active Expired - Lifetime
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3963828A (en) * | 1973-09-06 | 1976-06-15 | Siemens Aktiengesellschaft | Manufacture of uranium dioxide powder |
| EP0031066A1 (en) * | 1979-12-20 | 1981-07-01 | Alkem Gmbh | Process for producing nuclear-fuel oxides |
| CN86104023A (en) * | 1985-06-11 | 1987-04-22 | 三菱金属株式会社 | The method of convert from uranic fluoride to uranium dioxide |
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| Publication number | Publication date |
|---|---|
| CN1134918A (en) | 1996-11-06 |
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